internal class A<T> {
    fun foo(
        nonMutableCollection: Collection<String?>,
        mutableCollection: MutableCollection<String?>,
        mutableSet: MutableSet<T?>,
        mutableMap: MutableMap<String?, T>
    ) {
        mutableCollection.addAll(nonMutableCollection)
        mutableSet.add(mutableMap.remove("a"))
    }
}
